Purpose: To evaluate the safety and effectiveness of filgrastim (granulocyte colony-stimulating factor, G-CSF) in reducing neutropenia and treatment interruptions during whole abdominal radiotherapy for ovarian cancer.
Methods and materials: Sixteen patients with ovarian cancer treated with 2 to 6 courses of cisplatin-containing chemotherapy and abdomino-pelvic radiation therapy received filgrastim for neutrophil counts <2 x 10(9)/L. Endpoints for analysis included the ability to maintain the neutrophil count in the target range, number of treatment interruptions due to neutropenia, and toxicity attributed to filgrastim.
Results: Fourteen patients received a mean of 2.9 courses of filgrastim (each with a mean duration of 4.1 days), with no treatment interruptions due to neutropenia. The majority of neutrophil counts were maintained above the target range of 2 x 10(9)/L during treatment. Thrombocytopenia requiring treatment interruption was seen in six patients and necessitated platelet transfusions in one. Thrombocytopenia occurred at a mean abdominal radiation dose of 2207 cGy and in all but one patient was preceded by one or more episodes of neutropenia. In comparison with a control group of 31 patients treated without filgrastim there was no reduction in treatment interruptions. Four patients did not complete treatment because of persistent thrombocytopenia yet received a mean of 94% of the planned abdominal radiation dose and 69% of the planned pelvic dose. Filgrastim toxicity was limited to mild skeletal pains in six patients and a Grade 1 skin rash in two patients.
Conclusions: Filgrastim is safe and effective in preventing neutropenia and reducing neutropenic treatment interruptions during abdominal radiotherapy in patients with ovarian cancer. However, there was no clear benefit to the use of filgrastim as thrombocytopenia became the dose-limiting toxicity resulting in a risk of treatment interruptions and early termination of radiotherapy.